Patent GB-915919-A (GB)
Title: Apparatus for snapping glass sheets
IPC: C03B33/033
Filed: 1961-02-15
Abstract: 915,919. Cutting glass. PITTSBURGH PLATE GLASS CO. Feb. 15, 1961 [Feb. 15, 1960], No. 5594/61. Class 56. Scored glass sheets from a conveyer pass over a roller and are snapped as they pass over it by a further roller, located beyond and vertically reciprocable into contact with the glass, from above, in a cycle initiated by a feeler actuated by the leading edge of the glass. In the form shown, the glass sheet G is carried by rollers 20, between rollers 13, 14, over a roller 15, to a belt conveyer 16 at a slightly lower level. The rollers are in driving interconnections provided by a sprocket chain 27. The bearings for the roller 13 are vertically adjustable in guides 56, 57 on threaded rods 60. A roller 17 is carried in bearings similarly movable vertically in guides 78, 79 by an air cylinder 97 connected by links to the bearings. The cylinder is actuated to lower the roller on to the glass to snap it as each line passes over the roller 15. The timing mechanism by which this is done comprises discs 106, 107 carried on shafts 108, 110 and having peripheral holes 136 in selected ones of which may be inserted members 137 to operate switches 4LS (not shown), in the case of the disc 106, or 5LS in the case of the disc 107, these switches being adjustably mounted in arcuate slots 135 in brackets 131, 132. The shafts 108, 110 are interconnected by sprockets with a chain 118 and are initially at rest in a position when a cam 133 holds open a normallyclosed switch 3LS, being held stationary by an electromagnetic brake on the shaft 108. This shaft carries a sprocket 114 which rotates continuously, driven from the roller 15 through a reduction gear 123 and sprocket chains 127, 119. The sprocket 114 can be coupled to the shaft 108 by an electromagnetic clutch. The members 137 are inserted in holes 136 in the disc 106 selected to provide the timing for the snapping sequence required. A different sequence can be provided on the disc 107, the disc which is effective being selected by operation of a switch which connects either the switch 4LS or the switch 5LS into the control circuit. A cycle of operation is started when the leading edge of the sheet G trips a roller 104 to close a switch 1LS. This actuates a relay to free the electromagnetic brake on the shaft 108, and energize the clutch to couple the shaft and the shaft 110, which rotates with it, to the sprocket 114. The initial rotation allows the switch 3LS to close and this maintains the relay circuit even after the switch 1LS has closed so that the discs 106, 107 always complete one revolution until the switch 3LS opens again. As each member 137 passes the switch 4LS (or 5 LS, if that is the operative one) it closes it to energize a relay to actuate a solenoidoperated valve against a spring to supply air to the cylinder 97 and lower the snapping roller 17. The solenoid circuit is completed through two relay contacts, a normally open with a quick make and a normally closed with a slow break. The solenoid remains energized only for the time between the respective closing and opening of those contacts even if the switch 4LS remains closed.